Synthesis of new bis-imidazole derivatives

Abstract

The reaction of aldimines with α-(hydroxyimino) ketones of type 10 (1,2-diketone monooximes) was used to prepare 2-unsubstituted imidazole 3-oxides 11 bearing an alkanol chain at N(1) (Scheme 2, Table 1). These products were transformed into the corresponding 2H-imidazol-2-ones 13 and 2H-imidazole-2-thiones 14 by treatment with Ac2O and 2,2,4,4-tetramethylcyclobutane-l,3-dithione, respectively (Scheme 3). The three-component reaction of 10, formaldehyde, and an alkane-1,ω-diamine 15 gave the bis[1H-imidazole 3-oxides] 16 (Scheme 4, Table2). With Ac 2O, 2,2,4,4-tetramethylcyclobutane-1,3-dithione or Raney-Ni, the latter reacted to give the corresponding bis[2H-imidazol-2-ones] 19 and 20, bis[2H-imidazol-2-thione] 21, and bis[imidazole] 22, respectively (Schemes 5 and 6). The structures of 11a and 16b were established by X-ray crystallography. © 2007 Verlag Helvetica Chimica Acta AG.